The insert query, for some reason, defaults to inserting the entry with expid = 1 and will increment by 1 each time the query is run. As a result, on a fresh \i database.sql the query will fail 4 times until it gets to expid = 4 as up until that point it is trying to insert an experiment with an expid which is already used (we have 3 experiments by default -- the query successively tries to insert the experiment with expid 1, then 2, then 3, and will succeed with expid = 4 the fourth time it runs), violating the primary key uniqueness constraint. Subsequent runs of the query work fine and increment as expected.

I'm not sure why this is happening -- my guess is that it has something to do with the sql script and not the query as the query looks fine and the problem is not affecting other tables under similar circumstances.

            $query = "INSERT INTO database.experiments (name, payment, requirements) VALUES ($1, $2, $3)";

expid is not specified and should automatically take the next value in the series, but the table and its series appear to be out of sync.

I'm unable to reproduce it reliably at this point. It seems to happen more frequently around logins/outs.